Background: We investigated the prevalence of anosmia and ageusia in adult patients with a laboratory confirmed diagnosis of severe acute respiratory distress syndrome coronavirus-2 (SARS-CoV-2).

Methods: A retrospective observational analysis was conducted amongst patients and their household contacts across a central London population diagnosed with SARS-CoV-2 and admitted to hospital or managed in the community during March 1 - April 1, 2020. Symptomatology and duration were extracted from routinely collected clinical data. Descriptive statistics were used.

Findings: Of 386 patients with a laboratory diagnosis of SARS-CoV-2, 141 (92 community patients, 49 discharged inpatients) had evaluable data and were included for analysis. 77/141 (55%) reported anosmia and ageusia; nine reported only ageusia and three only anosmia. The mean duration of symptoms (as defined by the Public Health England case definition for SARS-CoV-2) was 13·1 days (0-33). The mean onset of anosmia in relation to onset of SARS-CoV-2 symptoms was 4·6 days (0-21). Duration of anosmia was 12·3 days (0-30). Duration of SARS-CoV-2 symptoms in community patients was 11·5 days (0-28) versus 16·7 days (0-33) in admitted patients. As of April 1, 45 patients had ongoing SARS-CoV-2 symptoms and/or anosmia. 107/141 (76%) patients had one or more household contacts during their isolation period. Of these, 185 non-tested household contacts, 79 (43%) had SARS-CoV-2 symptoms with 46/79 (58%) reporting anosmia. Six household contacts had anosmia only.

Interpretation: More than half of SARS-CoV-2 positive patients reported anosmia and ageusia. These findings suggest anosmia and ageusia should be added to case definitions for SARS-CoV2 and guide self-isolation protocols. This adaptation may be integral to case finding in the absence of population level testing. Until a time where we have successful population level vaccination coverage, these steps remain essential both in this pandemic and subsequent waves.Funding No specific funding was obtained for this work.

Funding Statement: This research did not receive any grant from funding agencies in the public or commercial sectors.

Declaration of Interests: EC has received speaker fees from bioMerieux (2019). NM has received speaker fees from Beyer (2016) and Pfizer (2019) and received educational support from Eumedica (2016) and Baxter (2017). LSPM has consulted for bioMerieux (2013), DNAelectronics (2015-18), Dairy Crest (2017–2018), Umovis Lab (2020), received speaker fees from Profile Pharma (2018- 2019) and Pfizer (2018-2020), received research grants from the National Institute for Health Research (2013-2020), CW+ Charity (2018-2019), and Leo Pharma (2016), and received educational support from Eumedica (2016–2018). AP, DLA, AA none to declare.

Ethics Approval Statement: Data was collected as part of routine care by the responsible clinical team. No patient identifiable data is reported in this analysis. The need for written informed consent was waived by the Research Governance Office of Chelsea & Westminster NHS Foundation Trust.